A peer-reviewed open-access journal ZooKeys 642: 1–52 (2017) feminine Hydroides 1 doi: 10.3897/zookeys.642.10443 CHECKLIST http://zookeys.pensoft.net Launched to accelerate biodiversity research Hydroides Gunnerus, 1768 (Annelida, Serpulidae) is feminine: a nomenclatural checklist of updated names Geoffrey B. Read1, Harry A. ten Hove2, Yanan Sun3,4, Elena K. Kupriyanova3,4 1 National Institute of Water and Atmospheric Research (NIWA), 301 Evans Bay Parade, Hataitai, Welling- ton 6021, New Zealand 2 Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, the Netherlands 3 Australian Museum, 1 William Street, Sydney, NSW, 2010, Australia 4 Department of Biological Science, Macquarie University, Sydney, NSW, Australia Corresponding author: Geoffrey B. Read ([email protected]) Academic editor: G. Rouse | Received 8 September 2016 | Accepted 29 November 2016 | Published 3 January 2017 http://zoobank.org/DE6CF77A-547B-4259-B41E-D1D79A0E5CFF Citation: Read GB, ten Hove HA, Yanan Sun Y, Kupriyanova EK (2017) Hydroides Gunnerus, 1768 (Annelida, Serpulidae) is feminine: a nomenclatural checklist of updated names. ZooKeys 642: 1–52. https://doi.org/10.3897/ zookeys.642.10443 Abstract As a service to taxonomists and ecologists using names in the well-known and species-rich ship-fouling serpulid genus Hydroides we present an update of all 107 non-synonymised scientific names, with additional information on Hydroides nomenclature, original names, etymologies, and type localities derived from original literature, and in accord with the World Register of Marine Species (WoRMS) database. An update is needed because the gender of genus Hydroides has from 1 January 2000 reverted to the original feminine, due to a change in the wording of International Code of Zoological Nomenclature which was overlooked at that time, and is contrary to the usage in practice of Hydroides as masculine which had started about 1992, although Code-required from the 1960s. We match 31 further original names of current WoRMS subjective junior synonyms to each non-synonymised name, and also report on the world distribution of the genus as illustrated by type localities of the valid names. We include notes on seven species inquirenda. The correct rendering is given of six names that have been altered for gender agreement for the first time herein. Hydroides gottfriedi nom. n. replaces junior homonym H. rostrata Pillai, 1971. Currently there are 41 non-synonymised species-group names in Hydroides which should be gender invariant, and 23 names which would only change if moved to a neuter genus; the remaining 43 names are fully gender variable. Place-names (23), and personal names (16) make up more than a third (36%) of the species names, with most of the remainder (68) being descriptive of species character states, usually of operculum morphology (54). All species, except H. norvegica (63°N), have type localities in shallow-water coastal locations in temperate to tropical waters below latitude 44°, with the highest number of new species (54) from the adjoining Western Pacific and Indian Ocean areas. The other concentration of new species (31) are those first found on the Pacific and Atlantic coasts of North America and in the Caribbean. Copyright Geoffrey B. Read et al.. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 2 Geoffrey B. Read et al. / ZooKeys 642: 1–52 (2017) Keywords Etymology, gender agreement, geolocation, ICZN, type locality Introduction An unusual situation has arisen concerning the correct formulation and spelling of historic species-group names in Hydroides Gunnerus, 1768 (Serpulidae) with respect to the established requirement of the International Code of Zoological Nomenclature (hereafter the Code) that the suffix spelling of a Latin or Latinized adjectival species- group name must agree in gender with its genus (ICZN 1999: Article 31.2). The stability of Hydroides names is important for tracking name usages as it is the largest serpulid genus, currently with 107 non-synonymised names, and also a further 31 original names currently placed as subjective synonyms. Hydroides includes H. elegans (Haswell, 1883), a model organism for settlement and genetic study (e.g., Hadfield 1998), and some other economically important species such as H. ezoensis Okuda, 1934, H. dianthus (Verrill, 1873), H. dirampha Mörch, 1863, and H. sanctaecrucis Krøyer [in] Mörch, 1863, which are foulers of ship hulls, harbour structures, and aquaculture equipment (Sun et al. 2015). Hydroides species are easily recognisable by the morphology of the plug which closes the mouth of their calcareous tubes. It is a two-tier operculum with a basal funnel and a distal spinous structure called the verticil. The distinctive and varied structure of the verticil spines has enabled many Hydroides species to be detected. Identification from tubes alone is problematic, thus past diversity is difficult to determine from the fossil record in the absence of the opercula. Hydroides has no current subgenera, but Eupomatus Philippi 1844, the most prominent junior synonym of Hydroides, and the little-used Eucarphus Mörch, 1863, were both at times used as subgenera defined by verticil morphology. The taxonomic history is reviewed in Bastida-Zavala and ten Hove (2002). We recently realised that the gender agreement serpulid taxonomists had been applying to adjectival Hydroides species-group names for the last 16 years was the opposite of that required by the fourth edition of the Code (ICZN 1999, effective 1 January 2000), in that authors since that date had continued using or creating masculine instead of feminine Latin forms. Additionally, taxonomists had not consistently observed the different Code rule applicable prior to 1999, with one author producing newHydroides names seemingly of both genders in the same publication (Straughan 1967a). Therefore we have compiled a checklist of Hydroides name spellings we believe are currently correct, including also identifying the names not subject to gender agreement. The derivation of Hydroides as an Annelida genus name is known. Stearn (1983: 266) explains that substantives derived from -oides were commonly used for new genera before and during Linnæus’ era to indicate resemblance to a genus already known, sometimes just as temporary names. The oides- suffix is originally adjectival, transliterated from Greek οειδης. Gunnerus had at first used the cnidarian genus of Hydra (named for the creature of Greek myth) as the genus name for his new tube- feminine Hydroides 3 dwelling worm in 1766 correspondence with Linnæus, but shortly thereafter changed it to Hydroides for his new species H. norvegica as published in 1768, “until Mr. v. Linné makes its genus known” (Gunnerus 1768, Moen 2006). The link to hydrozoans was spurious, but the genus name persisted. Usage of the same spelling applied to true hydrozoans persists in Romance language works, where “hydroïdes” (hydroids) can substitute for the formal higher group name, Hydrozoa. The pair of usages are not homonyms in the strict Code sense, but there is some false positive reporting of the Hydroides annelid genus in bioinformatics search results (e.g., from some of the Hydrozoa works of Billard, such as Billard 1907). Hydroides was feminine because Gunnerus clearly treated it as feminine when he used the feminine ‘norvegica’ as epithet for the worm instead of the masculine ‘norvegicus’ (likewise the calcareous tube was separately named Serpula norvegica by Gunnerus). However, in recent years Gunnerus’s original feminine gender assignment for Hydroides became not obvious to most. This is exemplified by Moen (2006), who in the summary of her historical paper on Gunnerus reports without qualification that “in 1768 J. E. Gunnerus first described the speciesHydroides norvegicus”. Although Moen was well aware Gunnerus did not use that spelling she perhaps believed the ‘correct’ masculine ending (although incorrect since 2000) was always to be used, regardless of what was originally written. The Code in its first edition indicated that genus names ending inoides - were to be treated as masculine (ICZN 1961: 33, Article 30(a)(ii) Examples), whereas in botany they were treated as feminine (Stearn 1983: 265). By the time of the Code third edition (ICZN 1985: 30, Article 30(b) Examples) the article text was the same, with the examples text explaining that these masculine genus names were substantivated adjectives, thus for Hydroides the adjectival descriptive of ‘hydra-like’ was functioning as a noun. Mandatory gender agreement, although much debated, was retained in the Code fourth edition, but changes were made in order “to simplify the identification of gender in genus-group names” (ICZN 1999: XXVI). Unexpectedly one of the qualifying clauses now included in the Code fourth edition (ICZN 1999) had a major effect on Hydroides Gunnerus by reverting it to feminine status after almost 40 years as the opposite gender. The wording of Article 30.1.4.4 in full is “A compound genus-group name ending in the suffix -ites, -oides, -ides, -odes, or -istes is to be treated as masculine unless its author, when establishing the name, stated that it had another gender or treated it as such by combining it with an adjectival species-group name in another gender form.” Why the Code editorial group thought the refinement was necessary is unknown, but presumably it was regarded as better matching contemporary practice with the original 18–19th century usages. Hydroides began as feminine in 1768, and feminine adjectival endings matching this were usual for over 220 years but not universal (e.g., H. bifurcatus Pixell, 1913). Hartman (1965: 79) had maintained original feminine endings in her supplementary world catalogue, although not long later she had used the masculine for H. pacificus Hartman (Hartman 1969). Masculine endings, which the Code had required from the early 1960s onwards, otherwise only became common around 1992 (Moen 2006: 4 Geoffrey B.